Inhalation of hydrogen-rich gas before acute exercise alleviates exercise fatigue.

Hydrogen, as an antioxidant, may have the potential to mitigate fatigue and improve selected oxidative stress markers induced by strenuous exercise. This study focused on previously unexplored approach of pre-exercise inhalation of hydrogen-rich gas (HRG). Twenty-four healthy adult men first completed prelaboratories to determine maximum cycling power (Wmax) and maximum cycling time (Tmax). Then they were subjected to ride Tmax at 80% Wmax on cycle ergometers after inhaled HRG or placebo gas (air) for 60-minute in a double-blind, counterbalanced, randomized, and crossover design. The cycling frequency in the fatigue modelling process and the rating of perceived exertion (RPE) at the beginning and end of the ride were recorded. Before gas inhalation and after fatigue modeling, visual analog scale (VAS) for fatigue and counter-movement jump (CMJ) were tested, and blood samples were obtained. The results showed that compared to placebo, HRG inhalation induced significant improvement in VAS, RPE, the cycling frequency in the last 30 seconds, the ability to inhibit hydroxyl radicals, and serum lactate after exercise (p < 0.028), but not in CMJ height and glutathione peroxidase activit. In conclusions, HRG inhalation prior to acute exercise can alleviate exercise-induced fatigue, maintain functional performance, and improve hydroxyl radical and lactate levels.

Characterizing the supraspinal sensorimotor control of walking using MRI-compatible system: a systematic review.

BACKGROUND: The regulation of gait is critical to many activities of everyday life. When walking, somatosensory information obtained from mechanoreceptors throughout body is delivered to numerous supraspinal networks and used to execute the appropriate motion to meet ever-changing environmental and task demands. Aging and age-related conditions oftentimes alter the supraspinal sensorimotor control of walking, including the responsiveness of the cortical brain regions to the sensorimotor inputs obtained from the peripheral nervous system, resulting in diminished mobility in the older adult population. It is thus important to explicitly characterize such supraspinal sensorimotor elements of walking, providing knowledge informing novel rehabilitative targets. The past efforts majorly relied upon mental imagery or virtual reality to study the supraspinal control of walking. Recent efforts have been made to develop magnetic resonance imaging (MRI)-compatible devices simulating specific somatosensory and/or motor aspects of walking. However, there exists large variance in the design and functionality of these devices, and as such inconsistent functional MRI (fMRI) observations. METHODS: We have therefore completed a systematic review to summarize current achievements in the development of these MRI-compatible devices and synthesize available imaging results emanating from studies that have utilized these devices. RESULTS: The device design, study protocol and neuroimaging observations of 26 studies using 13 types of devices were extracted. Three of these devices can provide somatosensory stimuli, eight motor stimuli, and two both types of stimuli. Our review demonstrated that using these devices, fMRI data of brain activation can be successfully obtained when participants remain motionless and experience sensorimotor stimulation during fMRI acquisition. The activation in multiple cortical (e.g., primary sensorimotor cortex) and subcortical (e.g., cerebellum) regions has been each linked to these types of walking-related sensorimotor stimuli. CONCLUSION: The observations of these publications suggest the promise of implementing these devices to characterize the supraspinal sensorimotor control of walking. Still, the evidence level of these neuroimaging observations was still low due to small sample size and varied study protocols, which thus needs to be confirmed via studies with more rigorous design.

Effects of endurance exercise on physiologic complexity of the hemodynamics in prefrontal cortex.

Significance: Prefrontal cortex (PFC) hemodynamics are regulated by numerous underlying neurophysiological components over multiple temporal scales. The pattern of output signals, such as functional near-infrared spectroscopy fluctuations (i.e., fNIRS), is thus complex. We demonstrate first-of-its-kind evidence that this fNIRS complexity is a marker that captures the influence of endurance capacity and the effects of hydrogen gas (H2) on PFC regulation. Aim: We aim to explore the effects of different physical loads of exercise as well as the intaking of hydrogen gas on the fNIRS complexity of the PFC. Approach: Twenty-four healthy young men completed endurance cycling exercise from 0 (i.e., baseline) to 100% of their physical loads after intaking 20 min of either H2 or placebo gas (i.e., control) on each of two separate visits. The fNIRS measuring the PFC hemodynamics and heart rate (HR) was continuously recorded throughout the exercise. The fNIRS complexity was quantified using multiscale entropy. Results: The fNIRS complexity was significantly greater in the conditions from 25% to 100% of the physical load (p<0.0005) compared with the baseline and after intaking H2 before exercise; this increase of fNIRS complexity was significantly greater compared with the control (p=0.001∼0.01). At the baseline, participants with a greater fNIRS complexity had a lower HR (ß=-0.35∼-0.33, p=0.008∼0.02). Those with a greater increase of complexity had a lower increase of the HR (ß=-0.30∼-0.28, p=0.001∼0.002) during exercise. Conclusions: These observations suggest that fNIRS complexity would be a marker that captures the adaptive capacity of PFC to endurance exercise and to the effects of interventions on PFC hemodynamics.

Effects of pre-exercise H2 inhalation on physical fatigue and related prefrontal cortex activation during and after high-intensity exercise.

Objective: In this study, we examined the effects of pre-exercise H2 gas inhalation on physical fatigue (PF) and prefrontal cortex (PFC) activation during and after high-intensity cycling exercise. Methods: Twenty-four young men completed four study visits. On the first two visits, the maximum workload (Wmax) of cycling exercise of each participant was determined. On each of the other two visits, participants inhaled 20 min of either H2 gas or placebo gas after a baseline test of maximal voluntary isometric contraction (MVIC) of thigh. Then participants performed cycling exercise under their maximum workload. Ratings of perceived exertion (RPE), heart rate (HR) and the PFC activation by using functional near-infrared spectroscopy (fNIRS) was measured throughout cycling exercise. The MVIC was measured again after the cycling. Results: It was observed that compared to control, after inhaling H2 gas, participants had significantly lower RPE at each workload phase (p < 0.032) and lower HR at 50% Wmax, 75% Wmax, and 100% Wmax during cycling exercise (p < 0.037); the PFC activation was also significantly increased at 75 and 100% Wmax (p < 0.011). Moreover, the H2-induced changes in PF were significantly associated with that in PFC activation, that is, those who had higher PFC activation had lower RPE at 75% Wmax (p = 0.010) and lower HR at 100% Wmax (p = 0.016), respectively. Conclusion: This study demonstrated that pre-exercise inhalation of H2 gas can alleviate PF, potentially by maintaining high PFC activation during high-intensity exercise in healthy young adults.